Pinobius acutus, Assing, 2018

Assing, Volker, 2018, A revision of Pinobius. II. Three new species from Cambodia and Indonesia, and additional records (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 50 (2), pp. 997-1004 : 999-1002

Pinobius acutus nov.sp. ( Figs 1-4 )

T y p e m a t e r i a l: Holotype ♂: " CAMBODIA - Kampong Chhnang prov., Kampong Chhnang env., Toul Ompel , 12°14'14''N, 104°41'15''E, light trap, 19+ 21.V.2018, leg. Bernardi, Kong & Rossi / Holotypus ♂ Pinobius acutus sp. n., det. V. Assing 2018" (cAss). Paratypes: 1♂, 1♀: same data as holotype (cAss).

E t y m o l o g y: The specific epithet (Latin, adjective) alludes to the apically conspicuously acute median lobe of the aedeagus.

D e s c r i p t i o n: Body length 9.1-10.8 mm; length of forebody 4.9-5.3 mm. Habitus as in Fig. 1 . Coloration: head and pronotum reddish-brown to dark-brown; elytra reddish with the anterior portion diffusely darker; abdomen reddish-brown to dark-brown; legs yellowish-red; antennae dark-reddish.

Head ( Fig. 2 ) 1.17-1.22 times as broad as long, broadest across eyes, relatively larger in the two males than in the female; lateral margins behind eyes subparallel or weakly tapering posteriad in dorsal view; punctation moderately coarse and moderately dense, somewhat sparser in median dorsal portion; interstices without microsculpture except for sparse and irregularly distributed micropunctation. Eyes slightly longer than postocular region in dorsal view. Antenna approximately 2.5 mm long.

Pronotum ( Fig. 2 ) approximately 1.05 times as long as broad and 0.9-1.0 times as broad as head; lateral margins subparallel; punctation relatively fine and moderately dense; interstices without micropunctation or other microsculpture; midline with moderately broad impunctate band.

Elytra ( Fig. 2 ) approximately as long as, or slightly longer than pronotum; punctation dense; interstices without microsculpture. Hind wings fully developed. Metatarsomere I slightly longer than the combined length of II and III.

Abdomen narrower than elytra; punctation fine and rather dense; interstices with fine microsculpture; posterior margin of tergite VII with palisade fringe; posterior margin of tergite VIII strongly convex.

♂: protarsomeres I-IV strongly dilated; sternite VII unmodified; sternite VIII with narrow and deep posterior excision; aedeagus ( Figs 3-4 ) 1.6 mm long, slender, and slightly asymmetric; median lobe of distinctive shape, with acute and transparent apex, in lateral view strongly curved and lamellate apically; parameres thin, of subequal length, not reaching apex of median lobe, and apically with four setae.

♀: protarsomeres I-IV strongly dilated, only slightly less so than in male.

C o m p a r a t i v e n o t e s: Based on the external and male sexual characters, P. acutus belongs to the P. indicus group (see ASSING 2014). It is reliably distinguished from other species of this group only by the distinctive shape of the aedeagus.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: The type locality is situated near Kampong Chhnang in the estuary of the effluent of Tonle Sap lake, Cambodia. The specimens were collected with a light trap, together with P. brevincisus and P. rossii .

Figures

Figs 1-8: Pinobius acutus nov.sp. (1-4) and P. rossii nov.sp. (5-8): (1, 5) habitus; (2, 6) forebody; (3-4, 7-8) aedeagus in lateral and in ventral view. Scale bars: 1, 5: 2.0 mm; 2, 6: 1.0 mm; 3-4, 7-8: 0.5 mm.